1. Field of the Invention
The present invention relates to an electrostatic recording head for causing a developing agent to electrostatically deposit on the surface of a recording member in accordance with a recorded image, and also to a method of producing this electrostatic recording head. The invention also is concerned with an image recording apparatus which employs this electrostatic recording head, as well as with a developing agent supplying device and a display device.
2. Description of the Prior Art
Image recording techniques of the kind described above are disclosed in, for example, Japanese Patent Unexamined Publication Nos. 59-219761, 58-171063, 60-58875 and 60-156074. In these known techniques, a magnet is disposed on one side of a recording electrode and the state of a developing agent (referred to as "toner" hereinafter) supplied into the gap between a recording electrode and a recording member is optimized by magnetic force developed by the magnet.
Furthermore, according to Japanese Patent Unexamined Publication No. 59-219761, a toner transported in accordance with the movement of the recording member is made to deposit to a recording electrode by the magnetic force developed by the magnet so as to form a stable chain (referred to as "toner chain" hereinafter) in the gap between the recording electrode and the recording member so as to ensure a stable image formation, i.e., stable printing. When the printing is not conducted, the toner chain serves as a barrier which prevents surplus toner from being transported together with the recording member.
Unfortunately, however, no specific consideration is given to the distribution of magnetism generated around the recording electrode by the magnet provided in the recording electrode. For instance, when a strong magnet is used to enable the "toner chain" to satisfactorily function as the barrier, a strong magnetic field is formed around the recording electrode. In order to enable the toner to attach to the recording member for the purpose of recording, it is necessary to break the toner chain by applying a recording voltage. When the magnetic field formed around the recording electrode is strong, the level of the recording voltage which is to be applied to overcome this magnetic field is correspondingly high.
Furthermore, the use of a strong magnet causes a thick barrier to be formed over a wide region, which seriously impairs the fluidity of the toner. This impedes smooth supply of the new toner failing to compensate for the consumption of the toner in the toner chain during printing, so that the cleanness and the resolution are rendered unstable and increase in the recording speed is practically limited.